Arrangement for feeding and burning liquid fuel



Dec. 16, 1958 2,864,439

ARRANGEMENT FOR FEEDING AND BURNING LIQUID FUEL R. VON LINDE ETAL FiledAug. 15, 1955 IN VE N T025 Rube/'2 van Linde 8 h/a/ferBaier UnitedStates Patent ARRANGEMENT FOR FEEDING AND BURNING LIQUID FUEL Robert VonLinde, Grafelfing, and Walter Baler, Stockdorf, near Munich, Germany,assignors to Wilhelm Baier K. G., Stockdorf near Munich, GermanyApplication August 15, 1955, Serial No. 528,473 Claims priority,application Germany August 23, 1954 9 Claims. (Cl. 158-5) This inventionrelates to a method and a device for supplying consumers, and moreparticularly burners, with liquid fuel and has special reference to afurther improvement of the device described in our copending applicationSerial No. 443,128, filed July 13, 1954, said device comprising anascending tube or riser provided in the fuel ducts leading from thesupply tank to the burner or other consumer, so as to ascend to a levelabove the level in the supply tank, and being exposed to the action ofheat at least in its-part below the supply tank level, to such an extentthat the difference between the two levels is overcome.

It is an object of the present inventionto provide a further improvementof this device, in such a way that even considerable differences oflevel between the supply tank and the consumer can be overcome.

A special object of the invention is to provide an In the accompanyingdrawings a now preferred embodiment of the invention is shown by way ofillustration and not by way of limitation. I

The figure is a side view of anoven, stove, or furnace including a fuelsupply system having the invention applied thereto, partly in an axialsection.

The exhaust gases of the oven 1 are discharged through a chimney 2.Mounted on the oven and ending in a combustion chamber in its interioris a funnel-shaped burner 3 which is supplied with evaporated fuelthrough an evaporator reservoir orv vaporizer 4 and a pipe 5.

' The right end of the burner 3, where the fuel supply arrangement inwhich the means on the supply tank suggested in our said copendingpatent application for keeping the fuel at a constant level can bedispensed with.

With these and further objects in view, according to the presentinvention the action of heat upon the part of the ascending pipe orriser communicating with the supply tank is increased to such an extentthat the liquid in the riser is at least partly evaporated. Thisintensive development of heat offers the advantage that the pressure inthe evaporating burner can be kept constant with the aid of an overflowreservoir, the difference of the level in the overflow reservoir and thevariable level in the supply tank being overcome without difliculty byheating and partly evaporating the liquid fuel in the heated portion ofthe riser. The fuel entering into the overflow vessel from the heatedriser is fed downwards, e. g., to an evaporation burner, excessive fuelflowing from the overflow reservior directly into the fuel tank througha cooled return pipe. In order to prevent vapors from accumulating inthe overflow reservoir, which vapors might cause variations ofdisturbances, the overflow reservoir is connected to the chimney of theoven, stove or furnace. I

According to a further feature of the present invention, referring toits application for the supply of burners with liquid fuel, the overflowreservoir is constructed in such a way that the fuel volume availabletherein including the column of liquid in the connecting pipe to theevaporation burner is smaller than the volume of the evaporationreceptacle. Hence, when the heating device is put pressure in theevaporating burner or other out of operation, for example, by accidentalinterruption of the supply of fuel to the heated riser, the burner flamewill go out for lack of evaporated fuel. As the evaporation reservoirthen remains partially filled with fuel,the

latter can evaporate if the burner is lighted again, as by pipe 5enters, isopen, whereby an annular slot is provided around this fuelpipe 5. Through said slot, air is sucked into the burner for thecombustion of the fuel when the fuel is fed from the reservoir 4 throughthe pipe 5. This annular slot, known per se, is not visible in thedrawing. The evaporator reservoir 4 through a pipe 6 is connected to anoverflow reservoir 7 which in turn is supplied with fuel from a fueltank 11 through pipes 8, 9, of which the latter is descending, and anascending pipe, of which a portion 10 passes through the combustionchamber to be intensively heated. The interconnected pipes 9 and 10constitute the legs of a U-shaped pipe system. Moreover, through a pipe12 the overflow reservoir 7 is connected to the chimney 2 of the oven 1.A further branch pipe 13, provided with cooling ribs 14, serves toreturn ingly the pressure under which the fuel is fed to the burner iskept constant with the result that a very uniform fuel supply isensured.

The fuel feeding device shown in the as follows: I

In order to put the burner into operation, the small supply of liquidfuel always remaining in the evaporator receptacle 4 is evaporated andthe burner is lighted, e. g. by a slow match. The flame will now heatthe length of pipe 10 in the :burner 3, whereby the fuel therein isintensively heated and partly evaporated, thus forming bubbles whichowing to their buoyancy will lift the liquid fuel column in front of theheating zone in the pipe it to the overflow reservoir 7, whereby thedifference between the level 15 in the tank 11 and the level in theoverflow reservoir 7 is easily overcome, even if the level 15 falls to aconsiderably lower position. The fuel in the reservoir '7 iscontinuously fed to the evaporation receptacle 4 through the pipe 6 andfrom the rec-eptable 4 to the burner 3 via the pipe 5, whereby thecombustion of the fuel is continuously maintained at a uniform rate offlow.

A part of the fuel, i. e., the overflowing fuel, is re turned to thetank 11, through the return pipe 13, where it is cooled by the coolingribs 14, so that it will not contribute to any appreciable rise intemperature of the fuel figure operates in the descending part 11, 8, 9of the fuel supply pipe the lower part of the annular chamber of thereceptacle The overflow reservoir 7 is constructed in such a way thatthe volume of the fuel therein, including that in the pipe 6, is alwayssmaller than the capacity of the evapo ration body 4, so that no morethan this amount of fuel can flow out from pipe 5 when the fuel supplyis shut off at 16.

It is also possible, however, to close a shut-off valve or cock 17 inpipe 5. In this case, the flame will go out immediately and theevaporated fuel, being prevented from entering the burner, will act toforce part of the liquid fuel column in the pipe 6 to return to.thereservoir 7, since the evaporation in the receptacle 4 continues for acertain length of time.

In order to re-start the burner, either the valve 16 or the valve 17will be re-opened and the small amount of fuel left in the evaporationreservoir 4 is evoprated and lighted.

The fuel feeding system according to the present invention proved to beparticularly suitable for the supply of burners with light liquid fuels,because the evaporating point of such fuels is within a temperaturerange readily obtainable in the combustion chamber without damaging thepipe 10. Suitably the heated portion of the pipe or riser is located ata lower level thereof, and preferably at the lowest part of theascending leg of the U- pipe system 9, 10, so as to assure that thebubbles of evaporating fuel cannot penetrate the liquid fuel column, i.e., rather they act like the piston of a pump to raise the column ofliquid fuel above them.

Thus, the fuel from the tank 11 is supplied to the evaporationreceptacle 4 and fed from there to the burner 3 without the use ofcomplicated devices, such as pressure-sensitive elements, etc.,heretofore employed. An additional advantage of the arrangementaccording to the invention resides in that it assures a safe operationif the burner flame should accidentally be extinguished, for example, bya sudden intense air current in the chimney 2. in such cases, thecontinued discharge of fuel vapors from the burner nozzle into thecombustion chamber has, heretofore, been a serious fire and explosionhazard, due to the possibility of re-igniting of accumulated fuel vaporsby contact with hot parts of the burner. Such conditions are positivelyprevented in the operation of a the arrangement according to theinvention, because the fuel is supplied to the burner only to the extentthat it is burnt. In case of accidental extinguishing of the burnerflame, the lifting action of the liquid fuel in the pipe or riser 10 isalmost immediately interrupted, so that no fuel will be fed to theoverflow reservoir 7 which is of limited capacity. As a result of this,only a small amount of fuel can flow from the reservoir 7 to theevaporation receptable 4 after the supply of fuel to this reservoir 7 isinterrupted. This small amount of fuel is no hazard, inasmuch as a partthereof remains in the evaporation receptable 4- in liquid conditionafter the flame has gone out.

While the invention has been described in detail with respect to a nowpreferred example and embodiment of the invention it will be understoodby those skilled in the art after understanding the invention thatvarious changes and modifications may be made without departing from thespirit and scope of the invention and it is intended, therefor to coverall such changes and modifications in the appended claims.

We claim:

l. An arrangement for feeding and burning liquid fuel, comprising afurnace having a combustion chamber, a combined vaporizer and burnerassociated with said chamber and being adapted to evaporate said liquidfuel and burn it, a tank for said liquid fuel being disposed higher thansaid combined vaporizer and burner, conduit means between said tank andsaid combined vaporizer and burner, said conduit means including agenerally U-shaped pipe having a descending leg and an ascending legconnected to said descending leg, the free end of the latter beingconnected to said fuel tank at its lower part, at least a portion ofsaid ascending leg of said U-shaped pipe being within said combustionchamber, the free end of said ascending-leg ending in an outlet abovethe top of said fuel tank, and descending conduit means connecting saidoutlet to said combined vaporizer and burner, whereby said fuel in saidascending leg is at least partially evaporated due to heating in saidcombustion chamber and the evaporation causes the fuel to ascend to saidoutlet from where it is discharged into said descending conduit meansleading to said combined vaporizer and burner.

2. An arrangement for feeding and burning liquid fuel according to claim1, wherein a valve means for shutting off the liquid fuel supply isprovided at the connection between said free end of said descending legand said fuel tank.

3. Anarrangement forfeeding and burning liquid fuel, comprising afurnace having a combustion chamber, a burner associated with saidchamber, a vaporizer at said burner and adaptedto evaporate said liquidfuel, means to connect said vaporizer to said burner to feed saidevaporated fuel thereto, a tank for said liquid fuel being disposedhigher than said vaporizer, conduit means between said tank and saidvaporizer, said conduit means including a generally U-shaped pipe havinga descending leg and an ascending leg connected to said descending leg,the freeend of the latter being connected to said fuel tank close to itsbottom, at least the lower portion of said ascending leg of saidU-shaped pipe being within said combustion chamber, the free end of saidascending leg ending in an outlet above the top of said fuel tank, anddescending conduit means connecting said outlet to said vaporizer,whereby said fuel in said ascending leg is at least partially evaporateddue to heating in said combustion chamber and the evaporation causes thefuel to ascend to said outlet from where it is discharged into saiddescending conduit means leading to said vaporizer.

4. An arrangement for feeding and burning liquid fuel according to claim3, wherein an overflow chamber is provided interconnecting said outletof said ascending leg and said descending conduit means, and wherein areturn flow conduit connects said overflow chamber to said fuel tank,said outlet and said return flow conduit ending in said overflow chamberat the same level and above the connection of said return flow conduitwith said overflow chamber.

5. An arrangement for feeding and burning liquid fuel according to claim4, wherein a cooling means is inserted in said return flow conduit.

6. An arrangement for feeding and burning liquid fuel according to claim4, wherein said overflow chamber has a fuel capacity which is smallerthan that of said vaporizer.

7. An arrangement for feeding and burning liquid fuel according to claim4, wherein the upper part of said overflow chamber is connected to anexhaust pipe for the gases collecting above the liquid fuel in saidoverflow chamber.

8. An arrangement for feeding and burning liquid fuel, comprising afurnace having a combustion chamber, a burner associated with saidchamber, a vaporizer at said burner and adapted to evaporate said liquidfuel, means to connect said vaporizer to said burner to feed saidevaporated fuel thereto, a tank for said liquid fuel being disposedhigher than said vaporizer, conduit means between said tank and saidvaporizer, said conduit means including a generally U-shapcd pipe havinga descending leg and an ascending leg connected to said descending leg,the free end of the latter being connected to said fuel tank close toits bottom, at least the lower portion of said ascending leg of saidUshaped pipe passing through said combustion chamber at a level belowthe connection of said free end with said fuel tank, the free end ofsaid ascending leg ending in an outlet above the top of said fuel tank,and descending conduit means connecting said outlet to said vaporizer,whereby said fuel in said ascending leg is at least partially evaporateddue to heating in said combustion chamber and the evaporation causes thefuel to ascend to said outlet from References Cited in the file of thispatent where it is discharged into said descending conduit means leadingto said vaporizer. UNITED STATES PATENTS 9. An arrangement for feedingand burning liquid fuel 477,872 Roberts June 28, 1892 according to claim8, wherein a valve means for shut- 5 1,567,815 Bavenor Dec. 29, 1925ting off the supply of evaporated fuel is inserted in said 1,629,722Michaud May 24, 1927 connecting means between said vaporizer and said2,587,078 Wollner Feb. 26, 1952 burner.

